French banker Olivier Sarkozy, the half brother of former French president Nicolas Sarkozy, and his young fiancé Mary-Kate Olsen, are scouring the city in search of their New York City dream house, Gimme Shelter has learned.

The odd couple has looked at a ton of available townhouses and has become notorious for making appointments to see townhouses and then cancelling.

“They make and break appointments faster than the speed of light,” one broker sniffed.

Sarkozy had bought 123 E. 10th for $6.25 million as a love nest in 2012, but the love birds never even moved in. He then sold it for $6.4 million last year. One of the townhouses they expressed interest in was a $22 million manse at 9 E. 94th St., on a street of Romanesque Revival homes built around 1892 by Cleverdon and Putzel.

The 20-foot-wide, 7,250-square-foot home is fully renovated and comes with a newly built curved staircase as well as an elevator. The couple, however, are looking for something less traditional and more paparazzi-proof, we hear, with a garage.

Vroom for rent

Do fancy fast cars catch your fancy? If so, check out this $15,000 a month rental at 554 Broome St., which was once owned by the late Ferrari dealer Roffredo Gaetani di Laurenzana dell’Aquila d’Aragona Lovatelli, an Italian count, prince and duke.

Currently occupied, the two-bedroom, two-bathroom duplex loft will be available for rent starting April 26. The loft boasts 16-foot ceilings, a “Ferrari red” kitchen, woodburning fireplace and a 15-foot-long oak dining-room table.

There’s also a century-old olive press, which was designed by Arturo Di Modica, known for his Wall Street bull sculpture. The listing broker is Douglas Elliman’s Frances Katzen.